Focal Tissue Stimulator
A focal tissue stimulator is provided that includes a pair of concentric conductors. The conductors may include an inner conductor, and an outer conductor that has an elliptical annular shape and surrounds the inner conductor. The outer conductor may have a minor axis and a mutually-perpendicular, major axis, with a first portion of the outer conductor proximate the minor axis being closer in proximity to the inner conductor than a second portion of the outer conductor proximate the major axis. In this regard, the inner and outer conductors may be coupled or couplable to respective leads configured to deliver current for passage therebetween, with the elliptical annular shape of the outer conductor creating a pathway of increased current density at the first portion relative to the second portion.
The present application claims priority to U.S. Provisional Patent Application No. 61/793,569, entitled: Focal Tissue Stimulator, filed on Mar. 15, 2013, the content of which is hereby incorporated by reference in its entirety.
TECHNOLOGICAL FIELDThe present disclosure relates generally to electrical stimulation of physiologic tissue and, in particular, to a focal tissue stimulator shaped to concentrate or focus stimulation current toward targeted physiologic tissue.
BACKGROUNDElectrical stimulation of physiologic tissue is common in medical practice. In particular, neural stimulation is a strong component of neurology/neurodiagnostics. This stimulation may be accomplished from skin surface stimulation, commonly called cutaneous stimulation or from direct nerve stimulation on exposed neural tissue when direct access to the nerve or brain tissue is available as is sometimes the case in surgery. The technique of electrically stimulating tissue is not without challenges. Two such challenges are electrical stimulus artifact and patient pain.
Electrical stimulus artifact occurs when current from the electrical stimulation electrode attachments flows in undesirable directions through tissue. For example, during stimulation of a nerve axon for purposes of depolarizing the nerve, the desired path for electrical current to flow would be from the attachment electrode cathode into tissue, through the desired nerve and back to the attachment electrode anode. In the ideal world, 100 percent of the delivered stimulating current would flow in this path without any current following alternate, undesirable pathways. However, in the real word, such ideal conditions do not occur and the delivered stimulating current flows in alternative, undesirable paths from anode to cathode in addition to the desired path through the targeted neural tissue. When these alternative, undesirable current pathways intersect with electrical recording activity, the result is the phenomena known as electrical stimulus artifact.
Electrical tissue stimulation can cause significant discomfort in the conscious patient. The pain results from the stimulation current activating tissue pain receptors. In order to minimize patient pain, it is desirable to activate the targeted neural (or other) tissue with the smallest possible delivered current while still facilitating the desired result in the targeted neural activation.
BRIEF SUMMARYExample implementations of the present disclosure provide a focal tissue stimulator shaped to concentrate or focus stimulation current toward targeted physiologic tissue. Multiple techniques may be used to make this happen, including the use of geometric points and ovals or ellipses. Typically, in stimulating human tissue, an electrode pair is used (an electrode at times referred to herein as a conductor), typically referred to as anode and cathode. The use of geometric points placed in strategic locations may shift current density from the electrode in a specific direction. Likewise, the strategic use of oval or elliptical shapes may facilitate current density patterns. In some instances, tri-polar stimulation may be used, in which the same or a similar focusing mechanism may be achieved via geometric features.
According to one aspect of example implementations, a focal tissue stimulator is provided that includes a pair of concentric conductors. The conductors may include an inner conductor, and an outer conductor that has an elliptical annular shape and surrounds the inner conductor. The outer conductor may have a minor axis and a mutually-perpendicular, major axis, with a first portion of the outer conductor proximate the minor axis being closer in proximity to the inner conductor than a second portion of the outer conductor proximate the major axis. In this regard, the inner and outer conductors may be coupled or couplable to respective leads configured to deliver current for passage therebetween, with the elliptical annular shape of the outer conductor creating a pathway of increased current density at the first portion relative to the second portion.
In various examples, the conductors or certain parameters of the conductors may vary to optimize the current density of the pathway. In some examples, a distance of either or both of the minor axis or major axis may be selected to optimize the current density of the pathway.
In some examples, the inner conductor may include a (one or more) first pair of opposing, outwardly-extending pointed features that lie on an axis of the inner conductor coincident with the minor axis of the outer conductor. Similarly, the outer conductor may include a (one or more) second pair of facing, inwardly-extending pointed features that lie on the minor axis of the outer conductor. Here, the pointed features of the second pair of pointed features may face respective pointed features of the first pair of pointed features to focus the current density of the pathway.
In some further examples, the pointed features of the first pair of pointed features may be symmetric about the axis of the inner conductor coincident with the minor axis of the outer conductor, and the pointed features of the second pair of pointed features are symmetric about the minor axis of the outer conductor.
In some examples, the length and/or sharpness of the pointed features of either or both the first or second pair of pointed features may be selected to optimize the current density of the pathway.
In some examples, the inner conductor may include a plurality of first pairs of opposing, outwardly-extending pointed features the plurality of which lie on the axis of the inner conductor coincident with the minor axis of the outer conductor. Similarly, the outer conductor may include a plurality of second pairs of facing, inwardly-extending pointed features the plurality of which lie on the minor axis of the outer conductor. In these examples, the pointed features of the second pairs of pointed features may face respective pointed features of the first pairs of pointed features to focus the current density of the pathway.
In some examples, the distance between adjacent pointed features of either or both the first or second pairs of pointed features may be selected to optimize the current density of the pathway. In some examples, the orientation of adjacent pointed features of either or both the first or second pairs of pointed features may be selected to optimize the current density of the pathway.
In some examples, the plurality of first pairs of pointed features may be symmetric about the axis of the inner conductor coincident with the minor axis of the outer conductor, and the plurality of second pairs of pointed features may be symmetric about the minor axis of the outer conductor.
According to another aspect of example implementations, a focal tissue stimulator is provided that includes a pair of concentric conductors. The concentric conductors may include an inner conductor, and an outer conductor surrounding the inner conductor, the inner and outer conductors having respective coincident axes. The inner conductor may include a first pair of opposing, outwardly-extending pointed features that lie on the axis of the inner conductor, and the outer conductor may include a second pair of facing, inwardly-extending pointed features that lie on the axis of the outer conductor and face respective pointed features of the first pair of pointed features. The inner and outer conductors may be coupled or couplable to respective leads configured to deliver current for passage therebetween, with the pointed features of the inner and outer conductors creating a pathway of increased current density relative to the first and second conductors absent the pointed features.
In various examples, the conductors or certain parameters of the conductors may vary to optimize the current density of the pathway, such as in a manner similar to that described above and in greater detail below.
According to another aspect of example implementations, a focal tissue stimulator is provided that includes a pair of conductors. The conductors may include a first conductor, and a second conductor separate from the first conductor. The first and second conductors may have respective first axes and mutually-perpendicular second axes. The first axis of the second conductor may be separate from but parallel to the first axis of the first conductor, while the second axis of the second conductor may be coincident with the second axis of first conductor. The first conductor may include an outwardly-extending pointed feature that lies on the second axis of the first conductor and faces the second conductor. And the first and second conductors may be coupled or couplable to respective leads configured to deliver current for passage therebetween, with the pointed feature of the first conductor creating a pathway of increased current density relative to the first conductor absent the pointed feature.
In various examples, the conductors or certain parameters of the conductors may vary to optimize the current density of the pathway, such as in a manner similar to that described above and in greater detail below.
According to another aspect of example implementations, a focal tissue stimulator is provided that includes three conductors. The conductors may include a first conductor, a second conductor separate from the first conductor, and a third conductor separate from the first and second conductors. The first, second and third conductors may have respective first axes and mutually-perpendicular second axes, with the first axis of the first, second and third conductors being separate from but parallel to one another, and the second axis of the first, second and third conductors being coincident with one another. The first and third conductors may include respective outwardly-extending pointed features that lie on the second axis of respective ones of the first and third conductors, and that face the second conductor. And the second conductor may include a pair of opposing, outwardly-extending pointed features that lie on the second axis of the second conductor, the pointed features of the pair facing respective ones of the first and third conductors.
The first, second and third conductors may be coupled or couplable to respective leads configured to deliver current for passage between the first and second conductors, and between the second and third conductors. The pointed features of the first, second and third conductors, then, may create pathways of increased current density relative to the first, second and third conductors absent the pointed features.
Similar to before, in various examples, the conductors or certain parameters of the conductors may vary to optimize the current density of the pathway, such as in a manner similar to that described above and in greater detail below.
According to another aspect of example implementations, a focal tissue stimulator is provided that includes a plurality of conductors arranged in a grid including a plurality of rows and columns. According to this aspect, the conductors may have respective first axes and mutually-perpendicular second axes. The first axes of the conductors in any row of the grid and second axes of the conductors in any column of the grid may be separate from but parallel to one another, and the second axes of the conductors in any row of the grid and first axes of the conductors in any column of the grid may be coincident with one another.
The conductors may include respective outwardly-extending pointed features that lie on either or both of the respective first or second axes, and that face adjacent conductors in the grid. In this regard, the conductors may be coupled or couplable to respective leads configured to deliver current for passage therebetween, with the pointed features of the conductors creating pathways of increased current density relative to the conductors absent the pointed features.
According to yet another aspect of example implementations, a focal tissue stimulator is provided that includes one or more depth electrodes. Each depth electrode may include a first electrical contact, and a second electrical contact separate from the first electrical contact, with the first and second electrical contacts being positioned on the electrode along a length thereof. The first and second electrical contacts may include respective outwardly-extending pointed features that face one another. And the first and second electrical contacts may be coupled to the electrode configured to deliver current for passage therebetween, with the pointed features of the first and second electrical contacts creating a pathway of increased current density relative to the first and second electrical contacts absent the pointed feature.
Having thus described example implementations of the present disclosure in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:
Some implementations of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all implementations of the disclosure are shown. Indeed, various implementations of the disclosure may be embodied in many different forms and should not be construed as limited to the implementations set forth herein; rather, these example implementations are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. Like reference numerals refer to like elements throughout.
In these examples, when the conductors 302, 304 (electrodes) are placed against tissue and electrically stimulated, the current density will tend to concentrate where there is a sharp point due to physics principles of charges concentrating on points such as those of the pointed features 316, 320. Being able to focus the current density between two conductors on tissue is very desirable. There are a number of benefits from being able to focus stimulation.
First, since the current is more focused on the target tissue, the clinician can deliver lower total current intensities while still delivering the same target tissue current density. In this case, the patient feels less pain upon stimulation. Second, focusing the current density means less current flowing in unwanted, alternate pathways. This inherently decreases the amount of current available to create electrical stimulus artifact. Third, the clinician will have a better knowledge of the current pathway and can place the conductors accordingly.
In various examples, as explained in greater detail below in
As shown in
As shown in
As shown in
The first, second and third conductors 602, 604, 606 may be coupled or couplable to respective leads configured to deliver current for passage between the first and second conductors, and between the second and third conductors. The pointed features 622, 624, 626 of the first, second and third conductors, then, may create pathways of increased current density relative to the first, second and third conductors absent the pointed features.
Similar to before, in various examples, the conductors 602, 604, 606, their pointed features 622, 624 or certain parameters of the conductors or their pointed features may vary to optimize the current density of the pathway, such as in a manner similar to that explained in greater detail below with reference to
Returning to the examples of
As shown in
In some further examples, the pointed features 532 of the first pair of pointed features may be symmetric about the axis 534 of the inner conductor 512, and the pointed features 536 of the second pair of pointed features are symmetric about the minor axis 516 of the outer conductor. Or in the case of multiple first and second pairs, the respective pluralities may be symmetric about the aforementioned axes. And in some examples, the orientation of adjacent pointed features of either or both the first or second pairs of pointed features may be selected to optimize the current density of the pathway, as shown in
Like
As shown, the focal tissue stimulator 900 includes a plurality of conductors 902 arranged in a grid including a plurality of rows 904 and columns 906. According to this aspect, the conductors may have respective first axes 908 and mutually-perpendicular second axes 910. The first axes of the conductors in any row of the grid and second axes of the conductors in any column of the grid may be separate from but parallel to one another, and the second axes of the conductors in any row of the grid and first axes of the conductors in any column of the grid may be coincident with one another.
The conductors 902 may include respective outwardly-extending pointed features 912 (only some of which are separately called out) that lie on either or both of the respective first or second axes 908, 910, and that face adjacent conductors in the grid of rows 904 and columns 906. In this regard, the conductors may be coupled or couplable to respective leads configured to deliver current for passage therebetween, with the pointed features of the conductors creating pathways of increased current density relative to the conductors absent the pointed features.
Similar to before, in various examples, the conductors 902, their pointed features 912 or certain parameters of the conductors or their pointed features may vary to optimize the current density of the pathway, such as in a manner similar to that described above with reference to
Reference is now made to
In the example of FIG. 10(B)—and similarly
Similar to before, in various examples, the electrical contacts 1014, 1018, their pointed features 1014, 1018 or certain parameters of the electrical contacts or their pointed features may vary to optimize the current density of the pathway, such as in a manner similar to that described above with reference to
Here again, in various examples, the conductors 1102, 1302, 1402, 1502, their pointed features 1104, 1304, 1404, 1504 or certain parameters of the conductors or their pointed features may vary to optimize the current density of the pathway, such as in a manner similar to that described above with reference to
In other examples, the focal tissue stimulator may be used with other types of electrodes such as electroporation electrodes, TENS electrodes, tab electrodes or the like.
Many modifications and other implementations of the disclosure set forth herein will come to mind to one skilled in the art to which these disclosure pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the disclosure are not to be limited to the specific implementations disclosed and that modifications and other implementations are intended to be included within the scope of any appended claims. Moreover, although the foregoing descriptions and the associated drawings describe example implementations in the context of certain example combinations of elements and/or functions, it should be appreciated that different combinations of elements and/or functions may be provided by alternative implementations without departing from the scope of any appended claims. In this regard, for example, different combinations of elements and/or functions than those explicitly described above are also contemplated as may be set forth in some of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.
Claims
1. A focal tissue stimulator comprising a pair of concentric conductors, the pair of concentric conductors comprising:
- an inner conductor; and
- an outer conductor having an elliptical annular shape and surrounding the inner conductor, the outer conductor having a minor axis and a mutually-perpendicular, major axis, a first portion of the outer conductor proximate the minor axis being closer in proximity to the inner conductor than a second portion of the outer conductor proximate the major axis,
- wherein the inner and outer conductors are coupled or couplable to respective leads configured to deliver current for passage therebetween, the elliptical annular shape of the outer conductor creating a pathway of increased current density at the first portion relative to the second portion.
2. The focal tissue stimulator of claim 1, wherein a distance of either or both of the minor axis or major axis is selected to optimize the current density of the pathway.
3. The focal tissue stimulator of claim 1, wherein the inner conductor includes a first pair of opposing, outwardly-extending pointed features that lie on an axis of the inner conductor coincident with the minor axis of the outer conductor, and
- wherein the outer conductor includes a second pair of facing, inwardly-extending pointed features that lie on the minor axis of the outer conductor, the pointed features of the second pair of pointed features facing respective pointed features of the first pair of pointed features to focus the current density of the pathway.
4. The focal tissue stimulator of claim 3, wherein the pointed features of the first pair of pointed features are symmetric about the axis of the inner conductor coincident with the minor axis of the outer conductor, and
- wherein the pointed features of the second pair of pointed features are symmetric about the minor axis of the outer conductor.
5. The focal tissue stimulator of claim 3, wherein at least one of a length or sharpness of the pointed features of either or both the first or second pair of pointed features is selected to optimize the current density of the pathway.
6. The focal tissue stimulator of claim 3, wherein the inner conductor includes a plurality of first pairs of opposing, outwardly-extending pointed features the plurality of which lie on the axis of the inner conductor coincident with the minor axis of the outer conductor, and
- wherein the outer conductor includes a plurality of second pairs of facing, inwardly-extending pointed features the plurality of which lie on the minor axis of the outer conductor, the pointed features of the second pairs of pointed features facing respective pointed features of the first pairs of pointed features to focus the current density of the pathway.
7. The focal tissue stimulator of claim 6, wherein a distance between adjacent pointed features of either or both the first or second pairs of pointed features is selected to optimize the current density of the pathway.
8. The focal tissue stimulator of claim 6, wherein an orientation of adjacent pointed features of either or both the first or second pairs of pointed features is selected to optimize the current density of the pathway.
9. The focal tissue stimulator of claim 6, wherein the plurality of first pairs of pointed features is symmetric about the axis of the inner conductor coincident with the minor axis of the outer conductor, and
- wherein the plurality of second pairs of pointed features is symmetric about the minor axis of the outer conductor.
10. A focal tissue stimulator comprising a pair of concentric conductors, the pair of concentric conductors comprising:
- an inner conductor; and
- an outer conductor surrounding the inner conductor, the inner and outer conductors having respective coincident axes,
- wherein the inner conductor includes a first pair of opposing, outwardly-extending pointed features that lie on the axis of the inner conductor, and the outer conductor includes a second pair of facing, inwardly-extending pointed features that lie on the axis of the outer conductor an face respective pointed features of the first pair of pointed features,
- wherein the inner and outer conductors are coupled or couplable to respective leads configured to deliver current for passage therebetween, the pointed features of the inner and outer conductors creating a pathway of increased current density relative to the first and second conductors absent the pointed features.
11. A focal tissue stimulator comprising a pair of conductors, the pair of conductors comprising:
- a first conductor; and
- a second conductor separate from the first conductor, the first and second conductors having respective first axes and mutually-perpendicular second axes, the first axis of the second conductor being separate from but parallel to the first axis of the first conductor, the second axis of the second conductor being coincident with the second axis of first conductor,
- wherein the first conductor includes an outwardly-extending pointed feature that lies on the second axis of the first conductor and faces the second conductor, and
- wherein the first and second conductors are coupled or couplable to respective leads configured to deliver current for passage therebetween, the pointed feature of the first conductor creating a pathway of increased current density relative to the first conductor absent the pointed feature.
12. The focal tissue stimulator of claim 11, wherein the second conductor includes an outwardly-extending pointed feature that lies on the second axis of the second conductor and faces the first conductor, the pointed feature of the second conductor further increasing the current density of the pathway.
13. The focal tissue stimulator of claim 12, wherein at least one of a length or sharpness of the pointed feature of either or both the first or second conductor is selected to optimize the current density of the pathway.
14. The focal tissue stimulator of claim 12, wherein the pointed feature of the first conductor is symmetric about the second axis of the first conductor, and
- wherein the pointed feature of the second conductor is symmetric about the second axis of the second conductor.
15. The focal tissue stimulator of claim 12, wherein the first conductor includes a plurality of outwardly-extending pointed features the plurality of which lies on the second axis of the first conductor and faces the second conductor, and
- wherein the second conductor includes a plurality of outwardly-extending pointed features the plurality of which lies on the second axis of the second conductor and faces the first conductor, the pointed features of the first conductor facing respective pointed features of the second conductor to focus the current density of the pathway.
16. The focal tissue stimulator of claim 15, wherein a distance between adjacent pointed features of either or both the first or second conductor is selected to optimize the current density of the pathway.
17. The focal tissue stimulator of claim 15, wherein an orientation of adjacent pointed features of either or both the first or second conductor is selected to optimize the current density of the pathway.
18. A focal tissue stimulator comprising three conductors, the three conductors comprising:
- a first conductor;
- a second conductor separate from the first conductor; and
- a third conductor separate from the first and second conductors,
- wherein the first, second and third conductors have respective first axes and mutually-perpendicular second axes, the first axis of the first, second and third conductors being separate from but parallel to one another, the second axis of the first, second and third conductors being coincident with one another,
- wherein the first and third conductors include respective outwardly-extending pointed features that lie on the second axis of respective ones of the first and third conductors, and that face the second conductor,
- wherein the second conductor includes a pair of opposing, outwardly-extending pointed features that lie on the second axis of the second conductor, the pointed features of the pair facing respective ones of the first and third conductors, and
- wherein the first, second and third conductors are coupled or couplable to respective leads configured to deliver current for passage between the first and second conductors, and between the second and third conductors, the pointed features of the first, second and third conductors creating pathways of increased current density relative to the first, second and third conductors absent the pointed features.
19. A focal tissue stimulator comprising:
- a plurality of conductors arranged in a grid including a plurality of rows and columns, the conductors having respective first axes and mutually-perpendicular second axes, the first axes of the conductors in any row of the grid and second axes of the conductors in any column of the grid being separate from but parallel to one another, and the second axes of the conductors in any row of the grid and first axes of the conductors in any column of the grid being coincident with one another,
- wherein the conductors include respective outwardly-extending pointed features that lie on either or both of the respective first or second axes, and that face adjacent conductors in the grid, and
- wherein the conductors are coupled or couplable to respective leads configured to deliver current for passage therebetween, the pointed features of the conductors creating pathways of increased current density relative to the conductors absent the pointed features.
20. A focal tissue stimulator comprising one or more depth electrodes each of which comprises:
- a first electrical contact; and
- a second electrical contact separate from the first electrical contact, the first and second electrical contacts being positioned on the electrode along a length thereof,
- wherein the first and second electrical contacts include respective outwardly-extending pointed features that face one another, and
- wherein the first and second electrical contacts are coupled to the electrode configured to deliver current for passage therebetween, the pointed features of the first and second electrical contacts creating a pathway of increased current density relative to the first and second electrical contacts absent the pointed feature.
Type: Application
Filed: Mar 14, 2014
Publication Date: Sep 18, 2014
Patent Grant number: 9415204
Inventor: Brett Lane Netherton (Prosperity, SC)
Application Number: 14/211,330
International Classification: A61N 1/04 (20060101);